The present embodiments relate to determining an irradiation plan for a particle irradiation system.
By way of example, an irradiation plan that defines control parameters for irradiating a test object is drawn up in advance during therapy planning in the case of particle therapy. The irradiation plan is used to plan the irradiation of an object in accordance with specific stipulations (e.g., target volume and dose distribution).
Particle therapy is an established method used, for example, to irradiate tissue attacked by tumorous diseases. In particle therapy, charged particles such as, for example, protons, carbon ions, or other ions are accelerated to high energies, shaped into a particle beam and guided via a high-energy beam transport system to one or more irradiation chambers. The target volume of the treatment object is irradiated with the aid of the particle beam in an irradiation chamber. Tissue outside the target volume may also be irradiated if so required.
In particle therapy with an active scanning method, individual grid points are irradiated with the aid of particle beams of different intensity (e.g., number of particle values per time unit). The different intensities are able to encompass a plurality of orders of magnitude. In this case, a monitoring system of the particle irradiation system is used for location measurement and intensity measurement using ionization chambers.
In this case, a grid point is not to be understood as a mathematic point in the target volume. Instead of this, the grid point defines a small surface or layer, mostly in the target volume, which is orthogonal to the particle beam. The particle beam thereby traverses the grid point or the layer defined by the grid point, and deposits along a track the dose to be applied. The largest proportion of the dose is applied or is intended to be applied in the “Bragg peak”.